The Northern Ireland RHI structure has been revised for boilers commissioned after 4th November 2015. The previous 20 – 99 kW size range as been increased to include boilers up to 199kW. In this 20 – 199 kW range, the first 1314 peak hours (1314 x boiler kWth) are paid at the Tier 1 tariff, any additional heat is paid at the Tier 2 tariff up to a maximum of 400,000 kWh.